Zverev needs to find another gear - and sharpish.

First, he must hold, but he skews a forehand into the tramlines to leave the game poised at 30-30.

That is a worldie of a drop shot from Stafenos Tsitsipas. Just superb.

Zverev gives his all to get to it - which he just about does - but he's always fighting a losing battle to return it.

Tsitsipas then wins the next point despite losing his racquet, and secures the hold.

He can't save the second break point though!

Zverev clips the top of the net and from 3-0 up in this second set, he now finds himself 4-3 down.

Tsitsipas is well and truly in control of this semi-final.

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Trouble for Zverev. Tsitsipas is in the mood again now.

The Greek drifts in to the net to kill the point with a sliced backhand and set up another break point.

But what a response from Zverev to save the first, nailing a backhand down the line that evades even the nimble Tsitsipas.

Outstanding from Tsitsipas. The Greek dances around the court, rescuing a point despite having one hand on the ground as he slides across the clay to get to 30-15 on the Zverev serve.

Tsitsipas keeps calm despite the increasing willingness of Zverev to move in from the baseline, and the Greek pulls level in the set.

Tsitsipas has only made one winner so far, which says something of the costly errors Zverev has made at crucial points.

The German thinks he's done enough to win a point at the net, but Tsitsipas recovers, digging out a backhand. 30-15.

Zverev saves the first, but Tsitsipas notches up the pressure once more and the German goes wide to concede the break.

That was all Zverev's own doing, the errors creeping in after a solid start to the game.

Tsitsipas takes charge of the rally, shifting towards the net and Zverev has no answer from his backhand.

Break back point.

Zverev looks to have fully recovered from his early jitters, a big cross-court forehand winner suggests.

But a double fault sets him back, and another error makes it 30-30...

Good serving from Tsitsipas. He aims for the Zverev backhand and it works a treat, the German hitting wide and Tsitsipas eases to his first game of the set.

Tsitsipas takes us to deuce, but that's as good as it gets for the Greek.

Fortune favours Zverev for the time being, as the sixth seed's forehand clips the net but drops on the other side.

Roles have been reversed in this second set.

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Zverev saves a dangerous situation, firing a forehand winner into the corner to pull level at 30-30.

Tsitsipas is having a word with himself after getting a forehand all wrong, which hands Zverev the chance to move 3-0 up in the set.

A big roar from the German. A couple of Tsitsipas errors are pounced on by Zverev, and at break point the Greek goes long.

Tsitsipas goes for the drop shot but Zverev is onto it in a flash to take a 30-15 lead.

The Greek responds, clipping the line with a forehand that Zverev can't send back.

That will do nicely.

A much more proactive Zverev reaches four aces for the match, before again springing in from the baseline to wrap up a comfortable hold.

Alexander Zverev gets us back up and running in the second set.

Hopefully the German can settle into things now. He sprints into the net and pounces on an inviting Tsitsipas return to get to 30-0. Good start.

The tension builds, but it's Zverev who blinks first. The German goes long from the baseline and it's fifth seed Tsitsipas who takes the opening set on Court Philippe Chatrier.

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Tsitsipas brings up the set point but cuts across a forehand that sails into the tramlines.

A real chance for Zverev to potentially rescue this first set...

Stefanos Tsitsipas to serve for the first set. Can Zverev deny him?

A cross-court backhand forces Tsitsipas into the net. 30-30. A chance.